I use the Subversion revision control system for all my development projects. It keeps a complete history of every change to every source file in each development project. As well as enabling me to determine exactly what source was used to build a particular version of a product, it also lets me find out what changes I made which introduced a problem or feature. Its branching and merging facilities make it possible for multiple developers to work on the same project without interfering with each other. But, as a friend on the CIX conferencing system once said, "a revision control system is vital for any projects with more than zero developers".
I also use Tortoise SVN as my Windows client for SVN. Here is how I set it up.
First download and install the latest Tortoise SVN. This will add itself into Windows Explorer, providing additional right-click options on files and folders. Now right-click on any folder, choose TortoiseSVN from the menu, and Settings from the sub-menu. You can change which of the many SVN options appear on the initial right-click menu, and which on the TortoiseSVN sub-menu in the "Look and Feel" section.
By default, Tortoise will check every folder on all your hard drives to see if they are SVN folders, and keep cached information about them. This can slow Windows Explorer a little if you have lots of folders. I keep all my SVN checked out sources in one of about 5 folders (one for each of my major customers, and one for my own development). You can tell Tortoise only to check these folders in the "Icon Overlays" section - untick all the "Drive Types" boxes, then add the paths to the "Include paths" box. Finish each path with "\*" (e.g. "C:\Development\*") to also include sub-folders.
If you use Tortoise to connect to report SVN repositories, you will usually use an "svn+ssh:user@domain/project/trunk" style of URL to tell Tortoise where to find the repository. If the repository's SSH server is on an unusual port (see Hacking SSH for details), you will need to configure ssh to use the port. To do this set up putty saved sessions for each of your SVN servers, using the appropriate user name, host name and port. Then use the saved session instead of a full username@domain - e.g. "svn+ssh:@savedsession/project/trunk".
I like to see the SVN revision number and status against all SVN files in Windows Explorer. To do this, display the folder in detail view, right click on the column headings at the top, choose "More...", and scroll down that list to the ones beginning SVN. Tick the ones you want (I like Status and Revision) and they will be included. You can then click on the Status column to sort your directory display with the modified files at the top.